Understanding a Gas Safety Certificate: A UK Homeowner's Guide
Published 13 August 2026 · Propvio Guides
A Gas Safety Certificate, sometimes called a CP12, is one of the most important documents a UK homeowner can hold. This guide explains what it covers and how to check it is genuine.
What a Gas Safety Certificate Covers
A Gas Safety Certificate records the results of a safety check on your gas appliances, pipework, and flues. It confirms whether each item is safe to use at the time of the check.
Landlords are legally required to have this check carried out every year by a Gas Safe registered engineer. Homeowners are not legally required to have one, but an annual check is still strongly recommended.
Checking the Engineer Is Genuine
Every Gas Safe registered engineer carries an ID card with their licence number and the types of gas work they are qualified to carry out. Ask to see this card before work begins.
You can check the licence number on the Gas Safe Register website. Do this even if the engineer has worked for you before, since registration can lapse or change.
Keeping Your Certificate With Your Property History
A Gas Safety Certificate is easy to misplace, particularly if it is kept as a paper copy. Losing it means starting again with no record of previous checks.
Keeping a digital copy alongside a record of who carried out the work means the certificate is available whenever you need it, including if you come to sell your home.
When to Renew Your Certificate
A Gas Safety Certificate is valid for 12 months from the date of the check. Set a reminder ahead of the expiry date so a new check can be booked in good time.
If you move into a property and cannot find a recent certificate, treat this as a reason to book a check as soon as possible, rather than assuming the gas appliances are safe.
This guide is for general information only and does not constitute professional advice.
Was this guide helpful?